1. Field of Invention
This invention relates to surface modifications and more particularly to immobilization of molecules to surfaces by photochemical coupling.
2. Description of Related Art
A common shortcoming of implantable medical devices or surfaces is recognition of these devices by an organism as foreign objects followed by inflammation or even a rejection of such devices. Surface modification science concentrates on finding a better interface between a living tissue and a solid matrix. It is known to use various coatings to impart desirable properties to implantable surfaces. Such coatings are based on polymers and may include biologically active materials. Challenges in preparing such coatings include attaching biologically active materials to inert surfaces.
One of the techniques for derivatizing inert surfaces is photochemical coupling (see reference [1]). Photo-cross-linking chemistry based on organic solvents is well established (see references [2-5]). It is not known to use adsorption from aqueous solutions for application of photo-cross-linkers onto a polymer surface.
Aryl ketones (e.g., benzophenone or acetophenone derivatives) and aryl azides are known as photo-activatable cross-linkers suitable for covalent binding to virtually any type of polymer surface as described by Amos et al. Upon irradiation with long-wave UV (at about 350 nm), benzophenone residues form energy-rich excited triplet species, which are then inserted into carbon-hydrogen bonds (C—H bonds) of a polymeric surface by abstraction of hydrogen atoms from C—H bonds and form new carbon-carbon bonds (C—C bonds), resulting in covalent binding of benzophenone residues onto the polymeric surface (see FIG. 1).
U.S. Pat. No. 5,071,909 to Pappin et al. discloses a method for immobilizing proteins or peptides onto a membrane by formation of a polymeric network, which entraps the protein or peptide.
U.S. Pat. Nos. 3,959,078, 5,512,329 and 5,741,551 to Guire et al. disclose covalent bonding of polymeric molecules to surfaces through external activation. This approach is used to bind fibronectin peptide to a polystyrene surface by a photo-reaction between the peptide and a surface having a photo-activatable group.
U.S. Pat. No. 5,637,460 to Swan et al. discloses attaching a target molecule (synthetic polymers, carbohydrates, proteins, lipids, nucleic acids, etc.) to a surface by using photo-activatable groups.
It is evident from the prior art discussed above that prior to the present invention, photo-cross-linkers were not used for the attachment of functional reactive groups (other than the same photo-activatable groups used in the initial step of photo-immobilization) to the surface in order to activate it for further immobilization of biomolecules.
Replication defective adenoviruses (Ad or AdV) have been extensively used in both experimental and human gene therapy. Ad cell entry takes place through receptor-mediated endocytosis via dual Coxsackie-Adenovirus Receptor (CAR)/αvβ3 integrins receptor system, although alternative pathways, such as fluid phase endocytosis might be operative under certain conditions (Meier and Greber, 2003). Various cell types differ widely in their level of CAR expression and this has proved to be a limiting factor for the level of transgene expression achievable with Ad. Furthermore, it is also clear that Ad cell entry and processing within cells via non-receptor endocytosis is a far less efficient means for vector processing than CAR-mediated cell entry. Thus, transgene expression in cells with relatively low amounts of CAR can only be achieved with high doses of Ad (Baker, 2004; Xu et al., 2005), and this has proved to be a major concern in terms of safety and toxicity (Yei et al., 1994; Thomas et al., 2001; Brunetti-Pierri et al., 2004).
Despite the foregoing developments, there is a need in the art for alternative means of attaching target molecules to surfaces.
All references cited herein are incorporated herein by reference in their entireties.